Catalytic oxidation of naphthalene



ll ntcnted l chm i932 SAEEE TENT OFFICE rhilllltllitflhl'il C JAEGER,01F GRAFTON, PENN$YILVANIA, ASSIGNQR TO'THE SELDEN CUM- PANY, UhPITTSBURGH, PENNfiYLVANIA, A CORPORATION GTE DELAWARE UAICAL'YTICOXIDATIQN 01F NAIPHTHALENE lilo Drawing". briginal application filedAugust 8, 19%, Serial No. 211,638. Illivided and this application filedMarch {26, 1928. Serial No. 264,975.

This invention relates to processes of oxidinii'ig naphthalene tointermediate oxidation products such as alphanaphthaquinonc, phthalicanhydride, maleic acid and the like. ltlore particularly the inventionis directed to processes of oxidizing naphthalene in the vapor phase.

.tccording to the present invention naphthalene is oxidized tointermediate products, especially in the vapor phase, in the presence ofcatalysts or contact masses which contain non-silicious base exchangebodies. Some of these new catalysts and contact masses have beendescribed and claimed as products in my Patent ll o. 1,694,620 datedDecember 11, 1928, of which the present application is in part acontinuation.

The non-silicious base exchange bodies used in the present invention maybe produced by the reaction of metallate components with metal saltcomponents under conditions so that the reaction mixture remainssubstantially alkaline to'litmus. 'l he invention is in no senserestricted to the use of catalysts which are the reaction products of asingle metallate and a single metal salt component, and some of the mosteffective catalysts for use in the present invention are the reactionproducts of a plurality of metallate components with one or more metalsalt components or a plurality of metal salt components with one or moremetallate components.

All of the base exchange bodies used in the 3 present invention, that isto say catalytically active bodies which are prepared by the reaction ofa single metallate with a single metal salt or bodies roducedby thereaction of at least one meta late with a plurality of 40 metal salts,or vice versa, possess a remarkably porous, frequently microporous,structure and in some cases are opalescent. When suitable catalyticallyactive components are present in the products, they form catalysts ofremarkable eificiency due probably to the extraordinarily high surfaceenergy of the microscopically porous structures and probably also to thepresence of unsaturated valences in many cases and a symmetry ofmolecules. It is of course possible that the catatures are present.

distinct products.

The molecular complexes which arev plexity, and the exact chemicalconstitution has not been determined. In fact it is not even definitelydetermined whether single chemical compounds are formed in any or allcases and it is possible that molecular mix- The products possess aphysically microscopical homogeneity and behave in many ways as if theywere single compounds, and I am of the opinion that probably in manycases the products are in tact single compounds of very high molecularweight, but the invention is not limited to any theories of the chemicalconstitution of the products.

It should be clearly understood that the products used in the presentinvention are chemically quite distinct from base exchanging bodiescontaining. silicon, such as for example the zeolites and related baseexchange bodies and their derivatives. The present compounds contain nosilicon in their structure, and while they share many of the physicalproperties of zeolites, namely, the highly porous structure and thepower of exchanging their alkali cations for other cations by baseexchange, they are chemically Surprising as it may seem,"the presence ofsilicon, which has hitherto been considered as essential to theformation of the skeletons of such advantageous physicalstructure,appears to be only one of many elements which are capable of bring--used in the present invention, it being understood of course that thechoice will depend on' the metal salts to be used and on the catalyticeffects which it is desired to pro.- duce. Among the elements-which formmetallates are the following :aluminum, chromium, zinc, vanadium,beryllium, tin, palladiu'm, platinum, titanium, zirconium, tungsten,uranium, tantalum, boron and molybdenum. The elements which form themetallates may be present. in the form of their oxides or hydroxidesunited with alkali to form simple metallates, or they may be presentpartly or wholly in the form of complex compounds, such as, for example,ammonia complexes, cyanogen complexes, and the like. In general, thecomplex compounds described in the prior patent of J aeger and Bertsch,No. 1,7 82,353 datedNovemberlS,1930,maybeused.

The metal salt components include the water soluble, neutral or acidsalts of the following elements :-copper, silver, gold, beryllium, zinc,cadmium, aluminum, rareearths,

titanium, zirconium, tin, lead, thorium, chromium, uranium, vanadium,manganese, iron, nickel, cobalt, platinum, palladium, which may be usedalone or in any desired mixture. It is an advantage of the presentinvention that definitevproportions of the individual compounds do notneed to be used, either because mixtures of different compounds areformed, or more probably because the tremendous size and complexity ofthe molecule masks any requirements for definite proportions.

All of the products used in the present invention possess baseexchanging powers to a greater or less extent when first prepared insolutions which are substantially neutral or moderately alkaline tophenolphthalein. For the oxidation of naphthalene, however, high baseexchanging power of the products is not required and it is thereforepossible to depart considerablyv from the optimum conditions ofproduction as far as baseexchange power goes, In other words, the limitsof alkalinity, neutrality or acidity are much wider than in the case ofproducts which are to be used for water softening, and which thereforedepend primarily on their base exchanging power. While usually thehighest base exchanging powers are obtained when the compounds areproduced in a reaction mixture which is substantially neutral ormoderatel alkaline to phenolphthalein, products having a similarphysical structure and being desirable for the catalytic oxidation'oforganic compounds can be prepared with somewhat 'diii'erent proportionsof the components, so that-at the end of the reaction the mixture maypossess any alkalinity or aciditytbetween phenolphthalein red and"litmus blue as indicator end points. j

' The possibilities of producing catalysts according to the presentinvention are not lunited to the reaction products of the metallates andmetal salt components which may be used and which are present in themolecules in a non-exchangeable form. On the contrary, a further seriesof products can be prepared ,by exchanging part or all of the alkalications for other atoms or radicals by means of base exchange. Thenumber of cations which can'be introduced is very large, and some ofthem are included in the following elements and radicals :ammonium,copper, silver, gold, beryllium, magnesium, caesium, zinc, strontium,cadmium, barium, mercury, aluminum, thallium, titanium, zirconium, tin,thorium, vanadium, chromium, uranium, manganese, iron, cobalt, nickel,palladium, platinum. These cations may be introduced either singly or inmixtures, simultaneously or successively. The wide possibilities ofcombination which can be effected by the introduction of various cationsby means of base exchange gives the catalytic chemist an almost infinitefield of choice in preparing catalysts having just the right degree ofactivity for organic oxidations and it is an advantage of the presentinvention that catalysts of exceedingly finely adjusted activity can beproduced and are effective. The cations introduced by base exchange maybe themselves catalytically active, or they may activate catalyticcomponents which are present in the products in non-exchangeable form.Cations may also be introduced as without the presence of cationsintroduced by base exchange, with products containing anions which arecapable of reacting with the base exchange body to form salt-likeproducts.

In the contact masses containing salt-like bodies which are used in thepresent invention the catalytically eflective components may be presentsolely in the base exchange body, solely in the anion of the salt-likebody, or partly in one and partly in the other. 0 Acid radicals of thefollowing elements,

either simple acids, polyacids or complexanions, can be used inproducing salt-like bodies with the base'exchange bodies of the presentinvention:'vanadium, tungsten, uranium, chromium, molybdenum, manganese,tantalum, arsenic, phosphorous, bismuth, sulfur, chlorine, platinum,boron.

Complex ions, such as, for example, ferroand ferricyanogen,sulfocyanogen metal cyanogen, and the like, may also be used whereeverthey form salt-like bodies with the base exchange bodies of the presentinvention. A single acid radical may be introduced, or a ea-seer mixturemay be used, either by a simultaneous or successive treatment. Theamount of the acid radical used may also be varied so that the productsmay possess the character of acid, neutral or basic salts.

"While it is possible to use certain of the catalysts of the presentinvention in an un diluted form, best results are usually obtained bythe dilution of the products with more or less inert bodies, or withbodies of relativeexchange body. lit should be understood of course inall cases that avhere a perfectly homogeneous product is desired. theincorporation of diluents must takeplace before the base exchange bodyafter formation has set. Practically all of the base exchange bodiesused in the present invention are first formed as gels, in whichcondition they can be incorporated with diluents or carrier bodies, butafter once setting, and particularly after drying, it is of courseimpossible to incorporate diluents into the base exchange body otherthan by purely mechanical mixture, which'in general is less desirable,but which is not excluded from the broader aspects of the presentinvention.

if large number of diluent bodies can be used, such as siliciousmaterials, as kieselguhrs of all kinds, diatomite brick refuse.

pumice meal, pulverized quartz, sand, and

other minerals, especially those rich in silica. in the same way, alarge number of natural or artificial massive carrier fragments can beused, such'as fragments of pumice, diatomite bricks or other minerals,metal granules and the like. In general. the methods of incorporation.and many of the diluents which can be used are described in thecopendintr application of Jaeger and Bertsch, Serial No. 95.771, filedMarch 18, 1926.

The high porosity of the products wh ch are prepared may be even furtherincreased by incorporating into the framework of the base exchange bodyproducts which can be removed by leaching, volatilization or-combustion,and which when removed leave additional porous spaces and produce'aneven more advantageous physical structure. The substances added may beof organic or inorganic nature and may be added as individuals or may bein chemical combination with'some of the permanent components. Thus, for

til?

example, certain of the components may be different methods.

many cases are of importance.

introduced in the form of complex compounds which are later decomposedand then leave additional porous spaces. Examples of such compounds arecertain ammonia complexes which can be decomposed by heating thefinished product.

In general, the reaction of the component solutions results in theproduction of soluble salts which are not wanted, and it is thereforeusually desirable to wash the base ex change body, after precipitation,and then to dry, or dry first and then wash. I have found that while itis possible in some cases to dry at high temperature, for the bestresults in most cases drying temperatures of 100 6., or less, aredesirable.

In the general methods described above, separately prepared metallatecomponents and metal salt components have been caused to react. Whilefor many purposes these are the. preferred methods, it is possible toprepare base exchange bodies by somewhat Thus, for example, if asolution of a metallate of amphoteric metal is'cautiously neutralizedwith acid until the strongly alkaline reaction becomes weakly alkalineto phenolphthalein, or even slightly acid with weak alkalinity to litmusas a limit, base exchange bodies are produced, and in Instead of themetallates, the amphoteric metals may also be present in the form ofcomplex metallate compounds, for example, such complex compounds as aredescribed in the co-pending application of Jaeger and Bertsch, referredto above.

In a similar manner, acid or neutral solutions of salts of amphotericmetals may be treated with alkali until the mixture becomes neutral oralkaline to phenolphthalein, or even acid, in which case base exchangebodies are produced in a manner similar to that described in-theforegoing paragraph. The base exchange bodies produced either byneutralizing metallate solutions or metal salt solutions in general donot show quite as great'base exchange power as do those which areprepared by causingready made metallate and metal salt solutions toreact with each other. The physical structure, however, appears to be 1similar and, as in many cases, particularly in the oxidation ofnaphthalene, extremely high base exchange power is not essential. Manyvery valuable catalysts can be'produccd in this manner.

A further wet preparation consists in causing alkali metal salts of theoxygen-containing acids of metal elements of the fifth and sixth groupsof the periodic system, such as for example, vanadium, molybdenum,tantalum, tungsten, and the like, to react with neutral or acid salts ofmetals, particularly metals which are strongly amphoteric. Preferablythere should be an excess of alkali. The salts of the fifth andsixth'group acids may loo be used alone or in combination with othermetallates.

In addition to the wet methods, which for most purposes I find arepreferable, base exchange bodies can be produced by fusion methods, forexample, by fusing oxides or hydroxides of the metallate and metal saltcomponents with alkali, such as, sodium carbonate or potassium carbonateor their hydroxides. The base exchange bodies pro.- duced by fusion,While sometimes they do not possess quite as high base exchange powers,are nevertheless of a similar advantageous physical structure, and manyof the products are very valuable catalysts. Oxides of the metals of thefifth and. sixth groups may also be used to form products somewhatsimilar to those described in the preceding paragraph by fusion methods.

The nonsilicious base exchange catalysts described above contain thecatalytically active element or elements in chemical combination withthe base exchange body or forming part thereof, and they are among themost effective catalysts used in the present invention. It is notnecessary, however, that the catalytic activity should reside in thebase exchange body itself, and many very important catalysts can beproduced in which catalytically inactive base exchange bodies are unitedwith catalytically active diluents to form physically homogeneousmasses. These masses, although they do not contain catalytic elementschemically combined with the base exchange body, of course share itsmicroporous structure, and where suitable catalytically active diluentsare used, catalysts of great efiiciency are obtained, and are includedin the scope of the present invention. Of course the catalytic activitymay reside both in the diluents and in the base exchange body.

The catalysts used in the present invention, and particularly dilutedcatalysts, may in many cases with advantage be given a preliminarytreatment consisting in a calcination,andexposure to oxidizing or acidvapors at an elevated temperature as described in my Patents Nos. 1.678,626 and 1,678,627 dated July 24, 1928. Such treatments frequentlyproduce secondary chemical changes as are produced in thecatalyses'themselves, and it should be understood that the catalysts ofthe present invention are defined as to chemical composition as of thetime when they-are freshly made, in accordance with the usual methods ofdefinition in catalytic chemistry.

Many of the organic reactions which are included in thepresentinvention, and particularly the oxidation of naphthalene,-require aslowing down, or stabilizing, of the catalysts used, in order to preventexcessive losses through total combustion, or to permit stopping at adefinite intermediate oxidation product with maximum yield. I have foundthat the presence of salts of alkali-forming metals and othernon-catalytic components may act as stabilizers, as may the oxides orhydroxides themselves in some reactions- Where the oxides or hydroxidesof alkaliforming metals are present, the catalyst should be subjected tocalcination with acid gases before use in order to avoid thepresstabilizers, and many of the amphoteric or other metal componentswhich are not selective catalysts for the particular oxidation re actionmay be considered, and act as stabilizer promoters. I do not claim inthis application the use of stabilizers or stabilizer promoters ingeneral, as these form the subjectmatter of my prior Patent No.1,709,853 dated April 23, 19529. The expressions stabilizers andstabilizer promoters, when used in the present application, are to beunderstood as used in the sense in which they are defined in theaforementioned co-pending application. It should be understood thatwhile many of the base exchange catalysts used in the present inventionmay be considered ascomposite stabilizers and stabilizer promoters, theinvention is not limited thereto, and stabilizers or stabilizerpromoters, or both, may be separately added to the catalysts of thepresent invention, and in fact many of the diluents, for example thosecontaining certain heavy or amphoteric metal compounds, are to beconsidered as stabilizer promoters.

The invention will be described in greater detail in connection with thefollowing specific examples which are illustrative merely, and do notlimit the broader scope of the invention. The examples, however, do inmany cases contain specific features which in their more narrow aspectsare included in the present invention. The examples give a few typicalreaction conditions and catalysts, but

it should be understood that the skilled catalytic chemist will choosewithin the confines of the present invention catalysts and reactionconditions best' suited to the particular installation in which he isinterested.

,Ewamp le 1 40 parts of V 0 are suspended in 500 parts of water andacidified with a little concentrated sulfuric acid. The suspension isheated almost to the boiling point and gases lilx till

. nuance"? cobtaining hltl are passed through until the vanadic acidsuspension is completely dissolved as blue vanadyl sulfate. ldometimesit is necessary to add some water in order to get the vanadyl sulfateentirely dissolved.

The blue solution is then divided into two parts, one of which is setaside and the other treated with ll. potassium hydroxide solution at 50to 60 C. until a clear coffee brown solution of potassium vanadite isobtained.

The vanadite solution is mixed with 70 parts of small diatomite brickfragments of parts of tlelite and 10 parts of quartz particles, themixture'being stirred until it becomes uniform. "Other diluent bodiessuch as neutral silicates, sand, silica gel, ground roclrs, tulfs, lavaof volcanic or eruptive or1- gin, or similar materials may be used. Tothe solution containing potassium vanadite the second half of thevanadyl sulfate solution is added, care being taken that even after allof the vanadyl sulfate has been added, the solution remains-alkaline orneutral to phenolphthalein. The reaction product, after separation fromthe mother liquor by filtration and drying at 60 to 70 0., is brokeninto fragments and constitutes a base exchange body containing potassiumand tetravalent vanadium, part of the vanadium playing the part of anacid radical and part that of a base in the non-exchangeable portion ofthe molecule. The base exchange body is then sprayed with 3 to 5%inorganic acids such as, for example, sulfuric acid, phosphoric acid,nitric acid, hydrochloric acid or the like until the potassium in theexchangeable part of the base exchange body has been neutralized and aso-called salt-like body is obtained. This salt like body tends tooxidize naphthalene to alphanaphthaquinone or phthalic anhydride,depending, on the proportions of air and naphthalene and on thetemperature. In general temperatures between 360 and 450 t). should beused.

Example 2 containing the mixture being heated almost to the boilingpoint. The blue solution obtained is treated with sufficient 2 N.potassium hydroxide solution to precipitate a voluminous brownprecipitate of V U which is then sucked and suspended in 200 parts ofwater. lit is then gradually warmed to ltl U and additional 2 hi.potassium hydroxide solution is added until all of the V 0 dissolves toform a codes brown solution. This requires an excess of potassiumhydroxide. The potassium vanadite thus produced is then stirred with 60parts of infusorial.

earth and 2 lil. sulfuric acid is gradually poured into the solutionwith vigorous agitation until the latter just remains alkaline to acidbrings down a brown precipitate while phosphoric acid brings down abrownish blue precipitate. The precipitates are pressed and then driedat temperatures below 100 C. The products thus obtained are saturatedwith a dilute waterglass solution formed of 110 parts of 33 Be.waterglass solution diluted with 100 parts of water. After impregnation,the product is again dried and broken into fragments and treated at 400to 450 C. with diluted burner gases in order to neutralize the alkali inthe base exchangeable part of the body.

The contact mass so prepared is an excellent catalyst for the catalyticoxidation of naphthalene to phthalic anhydride when a naphthalene vaporand air mixture in the proportion of about 120 is passed over thecatalyst at 370 to 400 0.

Example 3 Example 1,

20 parts of V 0 is reduced to a vanadyl sulfate solution as described inthe foregoing examples and is diluted with 60 parts of infusorial earth.2 N. potassium hydroxide is added in portions in the cold with vigorousagitation until the mixture just remains alkaline to phenolphthalein.The body precipitated is treated in the usual manner as described in theforegoing examples, and is'an excellent catalyst for the oxidation ofnaphthalene to phthalic anhydride, when a naphthalene vapor and airmixture in the proportion of 1:20 ispassed over the catalyst at 380-420C.

Example 5 18 parts of vanadium'pentoxide are suspended in 300 parts ofwater rendered weakly acid with concentrated sulfuric acid and reducedwith sulfur dioxide to blue vanadyl sulfate in the usual manner. Thesolution is boiled and concentrated to 150 parts of water. 10 parts ofaluminum oxide are transformed into potassium aluminate with 5 N.hydroxide solution. of the vanadyl sulfate solution is treated with 10N. potassium hydroxide solution to transform it into the coffee-brownpotassium vanadite which is then mixed with the sodium aluminatesolution and 100 parts of infusorial earth added.

Thereupon the remaining of the vanadyl sulfate solution is added withvigorous agi-. tation. The final reaction product should remain stronglyalkaline to litmus.

The product is pressed, dried as usual under 100 0., broken intofragments and then sprayed with 10% sulfuric acid until the socalledsalt-like body is formed. During-the spraying the fragments shouldpreferably be heated and stirred.

The product obtained after treatment with air at 400 C. is an excellentcatalyst for the vapor phase oxidation of naphthalene to phthalicanhydride when a mixture of naphthalene vapors and air in the proportionof 1 to 18 by weight is passed over the catalyst at 880 110 C.

Ewample 6' 1. A mixture of 10 parts of V 0 plus 4 parts of WC, aredissolved in 300 parts of diluted KOH solution containing 10.5 parts of90% KOH. About 90 parts Celite brick refuse or a mixture of comminutedquartz and diatomaceous earth equal in volume to the Celite brick refuseare added to this solution withvigorous agitation. The suspension isheated up to 8090 C. and is gradually made faintly acid to congo using 2N. sulfuric acid in order to precipitate out V 0 and WO in the diluent.The mixture obtained is then dried. v 2. 22 parts of Al (SO 18 aq. aretransformed in the usual way, with the help of ammonia, to Al (OH) andthe wet Al(OH) 8 is dissolved in 141 parts of'90% KOH using in 80 partsof water to form the corresponding aluminate.

The dried material obtained in #1 is impregnated with the aluminatesolution by kneading thoroughly and is then formed in suitable granules.These granules are then dried at temperatures preferably under 100 C. inthe presence CO containing gases whereby a diluted base exchange body isobtained containing V W0 and A1 0 in non-exchangeable form. I

The contact mass so obtained is calcined with air and then if necessarysprayed with mineral acids such as H SO HCl,HNO in order to form aso-called salt-like body. Sometimes it is preferable to saturate withchlorine gas. Contact masses thus obtained are very eflicient for thecatalytic oxidation of naphthalene to alphanaphthaquinone and phthalicand anhydride when treated with gaseous naphthalene mixed with air inthe ratios of 1: 15 to 1:20 by weight at 370 to 420 C. for themanufacture of phthalic anhydride and in ratios of 1 40 to 1: for themanufacture of alphanaphthaquinone.

Instead of V 0 and W0 other catalytically effective components can beused in this contact mass such asV O and M'oO Instead of using potassiumaluminate solution other metallates of elements with amphoteric propertycan be used such as cadmium and beryllium.

E wample 7 tion, precipitating out vanadyl silicate. Care should betaken that after all the solutions have reacted, the resulting mixturemust be made neutral to litmus, if necessarywith the help of smallamounts of N. sulfuric acid.

10 parts of freshly precipitated aluminum oxide are treated withsufficient N/2 KOH solution to dissolve up the aluminum oxide in theform of potassium aluminate and to provide a 510% excess of KOH.v

6 parts of V 0 are transformed as described above, to vanadyl sulfateand dis-.

solved in about 250 to 300 parts of water.

The vanadyl silicate obtained above is stirred in the vanadyl sulfatesolution and the potassium aluminate is added with vigorous agitationwhereby, a base exchange body is obtained containing V 0 and A1 0 innonexchangeable form diluted with vanadyl silicate and Celite brickrefuse. In adding the potassium aluminate, care should be taken thatafter all the aluminate is added the reaction mixture reacts at leastneutral or alkaline to phenolphthalein. If necessary small amounts ofadditional alkali can be added.

The reaction mixture is separated from the mother liquor in the usualway and then dried and broken into suitable pieces. After calcinationwith air at 400 C. in order to dehydrate the contact mass, diluted SOgases are passed over the contact mass to neutralize the alkali contentof the base exchange body.

The pretreated contact mass is very eflicient for the catalyticoxidation of naphtha- Ill) metal salt solutions are added to themetallate. solutions the alkalinity of the latter assures themaintenance of an alkaline reactio throughout the mixing.

'ln the'claims the catalysts are defined as oi the time when they arefreshly prepared because during catalysis or during calcination with airor acid gases the catalysts lose their base exchanging power. It shouldbe understood, therefore, that the claims are directed to the catalystas of the time when it is freshly prepared, but, of course, do notinclude catalysts which after being freshly prepared are subjected tofar reaching chemical treatment other than calcination with or withoutacid gases before being used in the oxidation of naphthalene.

This application is a division of m copending application Serial No.211,638, filed August 8, 192?,which matured into Patent No. 1,735,763dated November 12, 1929.

i /hat is claimed as new is: i y

1. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass containing at least onecompound included in the group consisting of non-silicious base exchangebodies salt-like bodies produced by the reaction of non-silicious baseexchange bodies with anions capable of forming salt-like bodiestherewith.

2. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass containing at least onediluted compound included in the group consistingi'o'f non-siliciousbase exchange bodies, salt-like bodies produced by the reaction ofnon-silicious base exchange bodies with anions capable of formingsalt-like bodies therewith.

3. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causin thevapors to react with anoxidizing gas in t e presence of a contact mass containing at least onenon silicious base exchange body, at least one catalytically activecomponent of the contact mass being chemically combined with thenon-silicious base exchange body.

4. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass containing at least onenonsilicious base exchange body, at least one catalytically effectivecomponent of the contact mass being chemically combined with thenonsilicious base exchange body in non-exchangeable :Eorm.

5. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors least onecatalytically eifective component of the contact mass being physicallyassociated with the non-silicious base exchange body 1n the form of adiluent.

6. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass contaimng at least onenon silicious base exchange body in which chemically combined vanadiumis present.

7. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass containing at least onediluted non-silicious base exchange body, at least part of the diluentscontaining vanadium compounds.

Signed at Pittsburgh, Pennsylvania, this 21st day of March, 1928.

ALPHONS O. JAEGER.

